Subacute toxicity evaluation in rats exposed to concrete and hwangto building environments

Abstract

This study examined the potential adverse effects of the subacute exposure of rats to concrete and hwangto building environments. Polycarbonate was used as a comparison. Groups of 10 male rats were exposed to polycarbonate, concrete, or hwangto cages for a 4-week period in summer or winter. During the study period, the clinical signs, mortality, skin temperature, body weight, food consumption, ophthalmoscopy, urinalysis, hematology, serum biochemistry, gross findings, organ weights, and histopathology were examined. The concentration of total volatile organic compounds (VOCs), temperature, and relative humidity in the each cages were also measured. There were no exposure-related effects in any group of the study examined in the summer. The temperature, relative humidity, and the concentration of VOCs in the cages were similar in all groups. However, in the winter study, significant differences in several parameters were detected among the groups. In the concrete group, there was an increase in the clinical signs, a reduction in the body weight gain, food intake, and liver weight, an increase in the lung weight, and an increase in the histopathological alterations in the lung and thymus. Infrared thermal analysis showed that the skin temperature of the rats in the concrete group was lower than that in the polycarbonate group. However, in the hwangto group, there was a decrease in the clinical signs and an increase in the body weight, food intake, and the weights of the heart, lung, spleen, and epididymides. Overall, the 4-week exposure of the rats to the concrete building environment had adverse effects on the clinical signs, skin temperature, body weight, and some organs in the winter but not in the summer. On the other hand, the exposure of hwangto building environment did not have any exposure-related adverse effects on the general health parameters and skin temperature in rats.

Evaluation of embryo‐fetal development in rats housed in concrete or hwangto cages during pregnancy

“…Therefore, it was concluded that the lower skin temperature induced by exposure to the low-temperature environment was the main cause of the adverse effects observed in the concrete group. In this study, the mean temperature (11.9-12.51C) of the internal air in the rat housing systems during the study period was similar to the results (11.7-12.11C) of a previous study (Lee et al, 2007). In addition, there was a higher incidence and severity of clinical signs in the concrete group than in the hwangto group, which is also consistent with a previous subacute toxicity study (Lee et al, 2007).…”

“…The incidence and severity of these clinical signs were somewhat higher in the concrete group than in the control and hwangto groups. These findings are uncommon in normal Sprague-Dawley rats (Kim et al, 2004(Kim et al, , 2006 but are consistent with the results of a previous subacute toxicity study (Lee et al, 2007). According to the subacute toxicity study, 4-week continuous exposure to concrete building environments under cool temperatures had significant adverse effects on the clinical signs, skin temperature, body weight, food intake, organ weight, and histopathology in rats.…”

“…Therefore, we considered that some adverse effects observed in the concrete group were not attributed to the inhalation exposure of tVOCs. This interpretation was well supported by the results of our previous study (Lee et al, 2007). In contrast, the concentration of tVOCs measured during the exposure period was much higher than that measured before placing the rats in each housing system.…”

“…The detailed protocols are provided in a previous report (Lee et al, 2007). Briefly, each housing system consisted of 6 individual cages constructed from polycarbonate, concrete, or hwangto.…”

“…Recently it was reported that the 4-week exposure of rats to a concrete building environment under cool temperatures had adverse effects on their clinical signs, skin temperature, body weight, and some organs (Lee et al, 2007). However, the rats exposed to the hwangto building environment did not show any exposure-related adverse effects on the general health parameters and skin temperature.…”